target/m68k/helper: Fix m68k_fpu_gdb_get_reg() use of GByteArray

target/m68k/helper: Fix m68k_fpu_gdb_get_reg() use of GByteArray

Since a010bdbe719 the gdbstub API takes a GByteArray*. Unfortunately
we forgot to update the gdb_get_reg*() calls. Do it now.

Fixes: a010bdbe719 ("extend GByteArray to read register helpers")
Reported-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20200409172509.4078-1-philmd@redhat.com>
Message-Id: <20200414200631.12799-11-alex.bennee@linaro.org>